Removing pits from peaches by automated machinery is performed by a peach pitting machine. In operation, this machine twists each peach half in opposite directions in an automatic peach pit twist operation. Whole peaches are first singulated by an infeed system when entering these machines. Singulated peaches are than processed through a peach aligner and transferred, one at a time, from the aligner into a set of rotatable heads, each with a peach gripper mechanism. A set of blades cut the peach in halves until the blades penetrate the peach far enough to grab the pit. The cutting blades are positioned perpendicular to the rotating axis of the peach twisting pitting heads. The heads then rotate in opposite directions, as the pit is constrained in a stationary position by the cutting blades. The rotating, or twisting motion of the two pitter heads, with the peach halves grabbed by the gripper mechanism of the heads, rips the meat of the peach from the pit, resulting in separation of the pit from each peach half.
The peach pitter heads each are typically a set of mechanically linked components, such as cam path mechanisms and/or lever arms, that are set up to rotate the gripper mechanisms through a set degree of rotation. Because the mechanical motion transmission components have a fixed profile, the peach head twister motion is always the same, typically in the range of 150 degrees. Unfortunately, mechanical components can not be readily adjusted to change the degree of head rotation. If a change in head rotation was desired, this would require a permanent change of components to create an alternate fixed set up.
For removal of the pit, as a matter of peach physics, the peach halves do not always have to rotate 150 degrees. With a solid pit, for example, the pit can sometimes be removed from the peach half by rotating the heads as little as 60 degrees. For these peaches, the motion required for the rotating pitter heads can be considerably reduced to remove a peach pit. A reduced rotating motion requires less time and allows for an increase in machine through put.
Peach quality, ripeness, firmness, etc., may require a slightly different head rotation to insure removal of the pit. Therefore peach pitter machines are always set up for the maximum head rotation. This has resulted in standard mechanical head drive components, which are typically set up for 150 degrees rotation.
Also, the peach pitter blades are provided with a selective knife. The selective knife, imbedded in the cutting blades, will only become functional when the pit can not be removed by rotating the heads. This will be the case when pits are weak or split inside the peach. Peach halves rotated in each head with a split pit can not develop a twisting force between pit and the peach half. As a result, the pit half will remain inside each peach half. To remove these half pits, the selective knife will become active and cut the pit from the peach half during rotation of the pitter head. Depending on the shape of the selective knife, the head must now be rotated exactly 150 degrees to insure the pit is removed from the peach half.
In short, the peach pitter heads can be rotated less than 150 degrees when removing the pit from the peach half by twisting the whole pit from the peach halves. But the heads must rotate 150 degrees when the selective knife cut is employed to remove the pit from each peach half.